Experimental and numerical investigation of reinforced cellular lightweight concrete beams under cyclic loading: performance assessment and regression analysis using response surface methodology

This research focuses on the development of lightweight concrete using industrial waste materials such as fly ash and Ground Granulated Blast Furnace Slag as partial replacements to promote sustainability in construction. The primary objective was to reduce the overall density of concrete without compromising its mechanical strength, making it viable for both structural and non-structural applications. Various mix proportions were tested, and the compressive and flexural strengths of cube and beam specimens were evaluated at 7 and 28 days of curing. The results demonstrated a significant reduction in weight, with optimized mixes maintaining satisfactory strength levels. Among them, the RC3 mix exhibited superior performance in both strength and density reduction. To further optimize the mix design and predict performance outcomes, Response Surface Methodology was employed alongside machine learning techniques, producing 100 predictive solutions. Contour and 3D surface plots provided insights into the interactions between replacement content and mechanical properties. Additionally, predicted versus actual strength graphs showed strong alignment, validating the model's accuracy. This study underscores the potential of lightweight concrete made with industrial byproducts as an eco-friendly alternative, offering a balance between structural integrity and reduced material usage, and contributing to the advancement of sustainable construction practices.